1. Field of the Invention
The present invention relates to an apparatus and method for fabricating an alignment layer for liquid crystal displays, capable of shortening process time, and preventing scratches of alignment layers and decreasing black luminance.
2. Discussion of the Related Art
In general, liquid crystal displays control light transmission of liquid crystals using an electric field to display an image. Such a liquid crystal display comprises a thin film transistor substrate and a color filter substrate, which face each other; and liquid crystals interposed therebetween.
The thin film transistor substrate comprises a gate line and a data line which intersect each other, a thin film transistor arranged at the intersection of the gate line and the data line, a pixel electrode connected to the thin film transistor, and a lower alignment layer formed to align a liquid crystal.
The color filter substrate comprises a color filter to render color, a black matrix to prevent light leakage, a common electrode to form an electric field with the pixel electrode, and an upper alignment layer formed thereon.
FIG. 1 is a perspective view illustrating a conventional method for fabricating an alignment layer for liquid crystal displays. As shown in FIG. 1, the conventional upper or lower alignment layer 14 is rubbed by rotating a rubbing roller 12, around which a rubbing cloth 10 is wound, on an organic polymer which is material of the alignment layer on a substrate 16.
As such, foreign materials or static electricity are generated in a region where the alignment layer 14 comes in contact with the rubbing cloth 10. These foreign materials remain on the alignment layer 14, causing display defects, such as spots. Meanwhile, the static electricity may cause breakage of thin films and thin film transistors.
In addition, liquid crystals are non-uniformly aligned in regions of the alignment layer 14 scratched by the rubbing cloth 10 and are non-uniformly aligned in regions where the rubbing cloth 10 does not contact the alignment layer 14 due to step coverage formed by a plurality of thin films arranged under the alignment layer 14. This non-uniform alignment induces light leakage, increasing black luminance and deteriorating contrast characteristics of liquid crystal displays.
Furthermore, when such an alignment layer is formed to large-area panels, uniform control of the rubbing roller 12 becomes difficult, thus preventing realization of uniform alignment of liquid crystals.